1812 Wrightwood earthquake
|Date||December 8, 1812|
|Magnitude||6.9 ML |
|Areas affected||Southern California
|Max. intensity||VIII (Severe) |
The 1812 Wrightwood earthquake, also known as the San Juan Capistrano earthquake, occurred on December 8 in Southern California 7:00 AM (Pacific time). It is thought to be the result of a rupture of the southern segment of the San Andreas Fault for an estimated length of 170 kilometers (110 mi) near Wrightwood, California, though the epicenter's location is not precisely known, and other proposed sources for the event exist. The earthquake had a magnitude of 6.9 and a maximum perceived intensity of VIII (Severe) on the Mercalli intensity scale.
Analysis of the what limited information is available about the earthquake was performed in the 1980s by seismologists Toussan Toppozada, Jack F. Evernden, and others. It is known that damage occurred in San Gabriel, and this group came up with a proposed epicenter along the south half of the Newport-Inglewood Fault zone, the source of the 1933 Long Beach earthquake. It was determined that the lack of damage at San Buenaventura, in what is now known as Ventura, limited the possible source of the event to that right-lateral fault.
Several of the Roman Catholic missions in the area experienced heavy damage. The Mission San Gabriel Arcángel's bell structure collapsed and at the Mission San Juan Capistrano forty American Indians were killed as the earthquake happened during the first service. The service was being held on a Tuesday, for the Feast of the Immaculate Conception celebration, which is universally celebrated every December 8.
- Stover, C.W.; Coffman, J.L. (1993), Seismicity of the United States, 1568-1989 (Revised), U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, pp. 72, 100
- Fumal, T. E.; Weldon II, R. J.; Biasi, G. P.; Dawson, T. E.; Seitz, G. G.; Frost, W. T.; Schwartz, D. P. (October 2002), "Evidence for Large Earthquakes on the San Andreas Fault at the Wrightwood, California, Paleoseismic Site: a.d. 500 to Present", Bulletin of the Seismological Society of America (Seismological Society of America) 92 (7): 2733, doi:10.1785/0120000608
- Ellsworth, W. L. (1990). "Earthquake history, 1769–1989". The San Andreas Fault System, California – USGS Professional Paper 1515. United States Geological Survey. p. 157. ISBN 978-0607716269.
- Bolt, B. (August 2005), Earthquakes: 2006 Centennial Update – The 1906 Big One (Fifth ed.), W. H. Freeman and Company, p. 33, ISBN 978-0716775485
- Wrightwood earthquake – Southern California Earthquake Center
- Historic Earthquakes – Southwest of San Bernardino County, California – United States Geological Survey